Very interesting idea.
Would you still open the sofa (and have the chair meet it)? You'd need a chair with a jacknife mechanism. I haven't seen anything like that.
In my R-Vision I have a dinette across from the sofa. When opened, the sofa meets the dinette to make a huge bed platform. Have you considered converting the two chair & table area into a dinette?
Class B vans with power sofas have ottomans. The sofa opens to meet the ottomans to make two "twin" beds or a queen bed using bolsters as fillers.